The technology disclosed in the specification relates to encoders and optical disk recording devices used for recording data onto optical disks, etc.
In recent years, HD (high definition) video broadcasting services and large-screen televisions have been dramatically increasing. With improvement in quality and resolution of video images, optical disks, as recording media for video images, have larger storage capacities. As large-capacity disks, Blu-ray Discs (hereinafter referred to as “BDs”) are known. In order to ensure an error correction capability for data recorded in high density, Long Distance Code (hereinafter referred to as “LDC”), which is obtained from user data, and Burst Indicator Subcode (hereinafter referred to as “BIS”), which is obtained from user control data, addresses, and flags, are defined in the BD format specification.
From addresses and flags, AUN (address unit number) parity symbols are generated, and these addresses, flags, and AUN parity symbols are interleaved. From data after this interleaving operation, BIS parity symbols are generated. The BIS parity symbols are recorded onto an optical disk together with the LDC. Related technologies are described in International Publication WO 2005/089075.
However, since BIS parity symbols are generated from interleaved data, one block of AUN parity symbols are all required to be generated in advance. For example, addresses, etc., stored in a storage device are read and AUN parity symbols are generated; the AUN parity symbols are written into the storage device; the AUN parity symbols are read from the storage device and interleaving is performed; and the result is again written into the storage device. Then, the interleaved AUN parity symbols, etc., are read and BIS parity symbols are generated, and then the BIS parity symbols are written into the storage device.
With such a process of BIS parity generation, since interleaving can only be performed after AUN parity generation, and since BIS parity symbols can only be generated after this interleaving, generation of BIS parity symbols requires a relatively long time to be performed. Moreover, since a large number of accesses are performed to the storage device, a large portion of the transmission bandwidth of the storage device is occupied. Furthermore, since AUN parity symbols, etc., generated during the process need to be stored, a storage device needs to have a large capacity.